From: Lukasz Luba <l.luba@partner.samsung.com>
Date: Tue, 4 Sep 2018 12:29:41 +0000 (+0200)
Subject: EXPERIMENTAL: sched/fair: find idle cpu in the group
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=0fd895c93b1a91065b3b6b71971662cb52c9d3fd;p=platform%2Fkernel%2Flinux-exynos.git

EXPERIMENTAL: sched/fair: find idle cpu in the group

In find_idlest_group take into account any CPU which is actually idle.

Signed-off-by: Lukasz Luba <l.luba@partner.samsung.com>
---

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index cdd3fc19b8f8..41a124a7d91c 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5668,6 +5668,7 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p,
 {
 	struct sched_group *idlest = NULL, *group = sd->groups;
 	struct sched_group *most_spare_sg = NULL;
+	struct sched_group *group_with_idle = NULL;
 	unsigned long min_runnable_load = ULONG_MAX;
 	unsigned long this_runnable_load = ULONG_MAX;
 	unsigned long min_avg_load = ULONG_MAX, this_avg_load = ULONG_MAX;
@@ -5676,6 +5677,8 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p,
 	int imbalance_scale = 100 + (sd->imbalance_pct-100)/2;
 	unsigned long imbalance = scale_load_down(NICE_0_LOAD) *
 				(sd->imbalance_pct-100) / 100;
+	bool found_local_idle = false;
+	int found_idle_cpu = -1;
 
 	if (sd_flag & SD_BALANCE_WAKE)
 		load_idx = sd->wake_idx;
@@ -5717,6 +5720,16 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p,
 
 			if (spare_cap > max_spare_cap)
 				max_spare_cap = spare_cap;
+
+			if (idle_cpu(i)) {
+				if (found_local_idle)
+					continue;
+				if (local_group)
+					found_local_idle = true;
+
+				found_idle_cpu = i;
+				group_with_idle = group;
+			}
 		}
 
 		/* Adjust by relative CPU capacity of the group */
@@ -5777,6 +5790,9 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p,
 		return most_spare_sg;
 
 skip_spare:
+	if (found_idle_cpu != -1)
+		return group_with_idle;
+
 	if (!idlest)
 		return NULL;